Detailed statistics to be used for optional repair

[Arkanosis]

Optionally (?) output the offsets and size of unrecoverable corrupted blocks to a file (eg. bamrescue.$PID.log).

This file could then be used to get the non-corrupted blocks from the original bam file to then repair the corrupted bam file without having to copy the whole original file again (expect a few kiB of non-corrupted bgzf block, instead of a few GiB of bam file).